A textile machine, for example, a ribbon lap machine, is stopped and a pilot lamp is lit upon the depletion of the lap feeding a lap sheet to the ribbon lap machine. Upon observing the lit pilot lamp, the operator interrupts the present work and goes to the ribbon lap machine, or goes to the ribbon lap machine after completing the present work, removes an empty bobbin, supplies a full lap, unwinds the lap sheet of the full lap, superposes the leading end of the lap sheet on the trailing end of the lap sheet remaining on the plate, and smooths down the superposed lap sheets for piecing. Since a usual ribbon lap machine, in general, has six delivery units, the lap piecing procedure is repeated six times, the ribbon lap machine is inched until the leading ends of the new lap sheets pass the curl plates, respectively, and then the ribbon lap machine is restarted.
Therefore, a textile machine, such as a ribbon lap machine, has a disadvantage in that the efficiency of operation thereof is very low, and accordingly, an automation of the lap changing operation is urgently required. Although the removal of empty bobbins and the supply of full laps can be achieved successfully by the conventional automated means, neither a practically effective automatic lap sheet piecing method nor an automatic lap sheet piecing apparatus for automatic lap sheet piecing operation, which is the most important operation, has been proposed.